The present invention relates to a vinylidene fluoride resin composition suitable for use as a coating material and the like.
Japanese Examined Patent Publication No. 10363/1968 discloses that a coating composition composed of a vinylidene fluoride (hereinafter referred to as "VdF") resin and an acrylic resin as main components has hitherto been applied to uses requiring a weatherability or a chemical resistance, e.g., anti-corrosive coatings for facing, oil tanks, pipes and ducts, and the like. In the composition, the acrylic resin is incorporated for enhancing a surface gloss and an adhesion to a substrate of the obtained film. However, the films obtained by baking the composition is insufficient in a chemical resistance due to the mixed acrylic resin.
On the other hand, Japanese Examined Patent Publication No. 6176/1974 discloses a coating method that the VdF resin is coated onto an epoxy resin primer. However, the VdF resin is poor in the compatibility with the epoxy resin primer, therefore cracks tend to occur on the surface of the film.
Also, Japanese Unexamined Patent Publication No. 500988/1980 or No. 60756/1986 discloses that when tetrafluoroethylene resin is admixed with a polyamide imide resin or an epoxy resin and the mixture is baked, the portion adjacent to the substrate of the formed film is predominantly composed of the epoxy resin and the portion adjacent to the outer surface is predominantly composed of the tetrafluoroethylene resin, and the film surface becomes chemically stable. However, when the polyamide imide resin or the epoxy resin is admixed with the VdF resin, cracks tend to be formed on the film obtained from the mixture, the reason being based on the fact that the VdF resin is poor in the compatibility with the polyamide imide resin or the epoxy resin.
It is an object of the present invention to provide a VdF resin coating composition capable of giving films having the excellent adhesion to substrate and excellent chemical resistance and having no cracks on its surface.
This and other objects of the present invention will become apparent from the description hereinafter.